Perforating device



Aug. 12, 1941- cgMlLLE PERFORATING DEVICE F11-ed Nov. 5, 1938 5Sheets-Sheet l Aug. 12, 1941. "L, c. MILLER PERFORMING DEVICE Filed NOV.5, 1938 5 Sheets-Sheet 2 gmc/M30@ All@ 12, 1941- c. MILLER PERFORATINGDEVICE Filed Nov. 5, 1938 5 Sheets-Sheet 3 Z D l '0040* e2 Z0 @wwwl////// |401/ Z D Aug. l12, 1941. L c. MILLER 2,252,270

PERFORATING DEVICE Filed Nov. 5. 1938 5 sheets-sheet 4r gramma/oo@Leon/'das C. /W/V/ev" Aug. 12, 1941. L, WLLER 2,252,270

PERFORATING DEVICE Filed Nov. 5, 1958 5 Sheets-Sheet 5 Patented Aug. 12,1941 PERFORMING DEVICE Leonidas C. Miller, Dallas, Tex., assignor toAmex'-L ican Oil Tool Company, Dallas, Tex., a corpo.

ration of Texas Application November, 1938, Serial No, 239,015

` y19 Claims; (Cll ici-csi' 'I'his invention relates to newfand usefulimprovements in perforating devices.

In the drilling of `oil wells andy the production of flowing wells, ithas become common practice to perforate the well casing alongits portionwhich extends through oil bearing sands and it is oney object of thisinvention to provide an improved perforating device for this purpose.

An important object of the invention is' to provide an improvedperforating device which is adapted to be lowered into a well casing ona wire line or cable and which includes a dry cell orv other battery forsupplying the electrical current forfiring the gun cartridges, of thedevice, whereby the necessity of conducting electrical current from thesurface for firing purposes, is eliminated and the running of the toolinto the casing, as well as the removalo'f the same therefrom,iseliminated.

A particular object of the invention is to provide a casing perforatorhaving improved control means for controlling the firing of thecartridges or projections, said vcontrol means being so constructed thatit may be setat the surface vprior to the lowering ofthe device into thecasing and being arranged so that it will auto-y matically fire thecartridges after a predeter?k mined time lapseand in a desired order, inac,-

cordance with the setting'or adjustment made at thesurface.

' Another object of the'invention is to provide an improved casingperforatorrincluding a plu'-v rality o f gun cartridges for perforatingfthe casving and having means for preventingunintentional or accidentalfiring of the cartridges during the lowering orraising ofthe devicelthrough the well casing, whereby saidl cartridges cannot be fired untilthe device is properly positioned in the desired location.

A further object of the invention is toprovide an improved perforator,yof the character described', which provides a double switch throughwhich the current must flow 4to the gun cartridges to fire the same; oneof said lswitchesl being associated witha 'mechanical latchingv meanswhich is arranged to positivelyprevent closing of.- said switch duringraising or lowering of the device through the well casing.

rStill another object of the invention is to provide a time'mechanismcarried by the device for controlling the firing of the cartridges,whereby said switch may be set at theA surface Ato automatically nre thecartridges at `any, predetermined time, thereby eliminating thenecessity of manually controlling the rlring from the surface,

A still further object of theinvention is to provide an improved casingperforator which is a self-contained unit and which has its source ofelectrical power and control switches mounted therein, whereby noconnecting or lead-in wires for current or control are necessary, whichgreatly facilitates handling of the device.

A construction designed tov carry out the invention will be hereinafterdescribed, together with other features of the invention.

The invention will be more readily understood from a reading of thefollowing speciilcationy and' by reference to the accompanying drawings,in which an example of the invention is shown, and wherein: l v

Figure l isa transverse; vertical, sectional view of the upper portionofan improved casing perforating device, constructed in accordance withthe invention,

Figure 2 is a continuation of the parts shown in Figure 1, showing theintermediate portion of ther device and illustratingthesafety switch andother" vparts in the position shown as the device is being lowered intothe well casing,

Figure' 3 is a continuation of the parts shown in Figure 2 andillustrating the lower portion ofthe device,

Figure 4 is an enlarged, transverse, vertical,l sectional of theintermediate portion ofthe de-l vice and showing thesafety switch'in a'closed] position after said device has been' properly po'f sitioned vinthe well casing,

Figure 5 is a continuation of the 'partsshown in Figure 4, with themechanical latching in its outward position,

Figure 6 is a' transverse, vertical, sectional means view, taken Aon theline 6 6 of Figure 1,

Figure 7 is a transverse, vertical, sectional view, taken` on thelinel-l of Figure 1,

Figure 8 isV a horizontal, cross-sectional view,

taken on'the line 8 8 of Figure 2,

Figure 9 isa horizontal, cross-sectional view,

takenon the line 9`9 of Figure 2,

Figure 10 is a horizontal, cross-sectionalview, taken on the line lli-I0 of Figure 2,

Figure 11 is a horizontal, cross-sectional vie'w,f

taken on the line Il-`-"l lof Figure 2,.,

-Figure 12 is a transverse, vertical; vsectional A View showing thelatch member in positionfduringthe raising of the f ievice'throughV theAwell casing,

Figure i3 is yawning diagram iuustratmg thev switch and'control meansfor tiring the "gun car'- tridges, l

Figure 14 is a view similar to Figure 1 and of the device, illustratedin Figures 14 to 17,.

with the said upper end connected to ground by means of a removablesleeve.

In the drawings, the numeral IIJ designates an elongate tubular sectionor sleeve which has its upper end provided with internal screw threads.A plug II closes the upper end of the sleeve or section I and the upperend ofv this plug has an annular retaining member or cap I2 ,threadedthereon. opening I2' formed in the cap andan annular shoulder I4, whichis formed on the lower end of the pin I3, is conned beneath said cap.The pin I3 is rotatable with relation to the retaining. cap I2. andthese parts form a 'swivel connection. The upper end of the pin I3 hasthe coupling I5 at the lower end of a cable or wire line I5 connectedthereto and, with this arrangement, the elongat'etubular sleeve orsection I0 issuspended from the cable. I

The lower end of the section I 0 is `formed with external screw threadsand is connected by means of a coupling collar I6 with a second or lowerelongate tubular sectionvH. A transverse plate or disk I8 is confinedbetween the ends oi" the sections IU and I1 (Figure 2), being clampedtherebetween and this disk separates theinterior of the section III fromthe interior of the section I1. Rotation of the disk I8 is prevented bymeans of dowel pins I9 which Vengage in recesses formed in said disk andinthe upper end of the lower section I1. The extreme lower end of thelower section I1 is formed withexternal screw threads which are threadedinto the upper end of a housing 20. cartridges 2| which are adapted tolbe red to perforate the well casing A, as will be explained.

The details of the housing 20, together with the particular constructionof the gun cartridges,

forms no part of the ApresentV invention and so long as said cartridgesare adapted to be fired by means of an electrical current, the purposesof the invention will be carried out. Also, it is pointed out that anydesired number of cartridges may be employed.

The sections I0 and I1 formfan elongate tubular housing or casing whichis separated by the transverse disk or partition J8. is suspended fromthe cable I5 and since its lower end is attached to the cartridgehousingV 20, it will be manifest that the latter housing is carriedthereby. The cable I5 may thus be utilized to lower the device withinthe well casing A to' a desired position therein.

The upper sectionv I0 is adapted to house a` socket 22 is mounted on thetransverse disk'` or A pin I3 projects through' an yaxial This housingcarries the.

This housing partition IB which separates the bore of the upper sectionI0 from the bore of the lower section I1. This socket is clearly shownin Figure 4 and includes an outer annular, elastic shell 23 which restsupon said disk. Rotation of the shell with relation to the disk isprevented by dowel pins 24, which engage recesses in the lower end ofsaid shell and the top of said disk. The shell is constructed of softrubber or other elastic, electrical non-conducting material and a socketbody 25 is mounted within the upper end of the shell, being molded orotherwise secured therein. The socket body is preferably constructed ofBakelite or similar material and a recess B is formed in the top of saidbody. A metallic contact sleeve B is mounted in said recess and servesto conduct an electrical current downwardly through the socket, as willbe hereinafter explained. An axial recess C having a contact sleeve vC'therein is located in the body and electrical current :is alsoconducted through this sleeve. A plurality of other recesses D are alsoformedin the body 25 and each recess has a contact sleeve D similar tothe sleeves B' and C. It is pointed out that the number of recesses Ddepends upon the number of cartridges contained in the'cartridge housing`2|), as one of these recesses is provided for each cartridge. Therecesses B and C do not lead directly to, or are not directly, connectedwith, a cartridge but lead through a safetyswitch, which will behereinafter explained.

A tubulancasing 26 is insertable within the upper section I0 and thelower end of this casing is closed by a plug 21, which is threaded ontoits lower end. Theplug. 21 is hollowed out and has its bottomclosed by.a disk 28 which is constructed of. Bakelite or similar material andwhich is suitably fastened in the plug. The disk carries a contact prongB2 which is adapted to engage within the contact sleeve B 'in the recessB whenthe casing 26 is in position within the section IIL A similarcontact prong .C2 is located axially of the disk 28 and is arranged toengage within thecontact sleeve C' of the recess C. fA, plurality ofadditional contact prongs D2 `are also mounted in the disk 28 and areadapted to engage` within4 the contact sleeves DT within the recesses D.With this arrangement, it will be obvious that when the tubularcasing`26 is in position within the section I0, the contact prongs B2,,C2 and D2 are engaged within their respective contact sleeves so thatan electrical connection is set up between said prongs and said sleeves.

The casing 26jextends upwardly substantially throughout the length ofthe section I0 and said casing is preferably formed in two sectionswhich are connected together by means of a coupling plug 23, said plugbeing threaded to the two sections of said casing. A switch assembly S,which carries-the control mechanism` fory controlling the firing of thecartridges', as will be hereinafter explained, is mounted within thetubularv casing 26 between the plug 29 andthe lowerniost plug 21. Thisswitch assembly `is clearly shown in Figures 1, 6 and 7 and includesapairof side plates 30 and 3tlgI which are 4spaced from each other andwhich extendbetween the plugs 21 and 29. As is clearly shown 'in Figure1, the upper plug 29 is formed with a depending angular lug 3| and theextreme upper ends oi' the side plates 3U and 30 are suitably fastenedtothis'lug. The lower ends of the plates 30 and 30 aresimilarly fastenedto an upstanding collar or lug 32 which is preferably formed integralwith the plug 21. In this manner, the side plates 30 and 30' are rigidlymounted Within the tubu-y lar casing 26.

Mounted between the side plates 30 and 30' near the upper ends thereofls a timer mechanism T. This mechanism is of standard construction,being actuated by means of a flat spring 33, which spring has one endsecured to a shaft 34. The shaft extends through andy is journaledwithin the side plate 30 andy has a winding key 35 located on the outerside of the plate 30. A suitable opening 36 is formed in the tubularcasing 26, whereby access to the key 35 may be had. The opposite end ofthe at spring 33 is fastened by means of a rivet 31 to the inner wall ofthe side plate 30. A gear train or mechanism is driven by the shaft 34and this mechanism is such as is used in a Watch. 'Ihe details ofthemechanism are not shown since it is of ordinary construction, themechanism yserving to require a predetermined length of time for theshaft to complete one revolution. The mechanism includes a pinion 38 andan enlarged gear 39, which is fastened on a stub shaft 40 which isjournaled in the plates 38 and 30' below the spring 33. One end of theshaft 40 extends outwardly through the side plate 30' and has a cam 4|secured thereto. This cam has a recess 42 (Figure 13) formed in itsperiphery. Obviously, when the spring 33 is wound it is placed under atension and, as said spring unwinds to return to a normal position, theshaft 34 is rotated to rotate the pinion 38. Rotation of the pinionimparts a rotation to the cam shaft 4|) through the medium of the geartrain 38 and, therefore,

the cam 4| is rotated. The timerT may be constructed so that it willtake any given length of time for the cam 4| to complete one revolution,lthat is, it may take thirty minutes or it may take sixty minutes,depending on howv long it takes the gear train to impart suflicientrotation to the shaft 34 to cause the cam shaft 40 to make a 1 completerevolution.

An elongate operating arm or lever is pivoted on a pin 44 on the outerside of the side plate 30'. The upper end of this lever extendscontiguous to theperiphery of the cam 4| and a lug 45 on said lever isarranged to ride on the surface of said cam, being held -in engagementwith said cam periphery by a coiled spring 46 (Figure 7). The upper4 endof the lever 43 is offset and is provided with a roller 41. This rolleris arranged to engage a spring switch blade 48, which blade is mountedon an angular bracket 49 secured to the outer surface of the plate 30.The switch blade 48 is movable between an electrical contact 50 mountedon a bracket 5| secured to the plate, and a second contact 52 which issecured rto a second bracket 53. When the lug 45 on the operating lever43 is riding on the periphery of the cam wheel 4| the switch blade 48 isin engagement with a contact 50. However, when the cam 4| has'rotated acomplete revolution to move the recess 42 opposite the lug 45, said lugenters the recess, whereby the operating lever 43 is swung on the pivot44. Such swinging of the lever 43 causes the upper end of said lever tomove the switch blade 48 out of engagement with the contact 50 and toengage said blade with the contact 52. The electrical circuits which areclosed and opened by the engagement of the blade 48 with the contacts 50and 52 will be hereinafter described.

The lower end of the operating lever 43 isbent upon itself atsubstantially a right angle to form a projecting lug 54. When the lug 45.at the upper vportion of the lever 43 is riding on the periphery of thecam 4|, the lever 43 is in a position, with the lug 54 at its lower endengaging within a recess 55 provided in the periphery of a circular camdisk 56, whereby rotation of the cam disk 56 is prevented. Whenever thelug 45 drops into the recess 42 on the cam 4|, the lever 43 is swung,which swinging disengages the lug 54 from-the recess 55 in the cam 56and, when this occurs, the cam 56 is capable of-rotation. The cam 56 ismounted on a shaft 51 which is journaled in the side plates 38 and 30',as clearly shown in Figure 1. The cam 56 is located on the outer side ofthe plate 38', while a gear 58 is fastened on the shaft 51 adjacent theinner side of said plates. The gear 58 is in constant mesh with a gear59, Which latter gear meshes with an operating pinion 60. The pinion 60is mounted on la shaft 6| which is journaled in the plates 30 and 30 andthe outer end of the shaft 6| is provided with a winding key 62 which islocated within an opening\l63 formed in the outer tubular casing 26. Aflat spring 64 has one end secured to the shaft 6| with its opposite endfastened by meansof a rivet 65 to the inside of the plate 30. 'I'hewinding key 62 is utilized to rotate the shaft in a direction to windthe spring 64 and place the same under a tension. The shaft 6| isconnected with the cam 56 through the gears 58 and 59 and the pinion 68vand when the spring 64 is placed under a tension, the recess 55 in thecam 56 is opposite the lug 54 on the operating lever 43, whereby saidlug may engage within said recess to prevent rotation of said cam. Whenrotation of the cam is prevented, rotation of the shaft 6| is alsoprevented and, therefore the spring 64 cannot unwind until the lug 54 isdisengaged from the recess 55 permit rotation of the cam 56.

Since the cam 56 is mounted on the shaft 51, it will be manifest thatsaid shaft is rotated when the cam disk 56 is rotated. The shaft 51 exftends through the plates 30 and 30 and has a switch arm 66 keyed orotherwise secured thereto, whereby when the shaft51 is rotated theswitch arm 66 is also rotated. A contact 61 is secured to the outerendof the arm 66 and is arranged to travel over a plurality of contacts68 which are mounted in a commutator disk 69 which is suitably mountedwithin the side -plate 30.` With this arrangement, it will be manifestthat when the switch arm is rotated it will successively engage vth-econtacts 68 on the commutator disk as it completes one revolution. Thecontacts 68 are connected-k to the cartridges 2| located in thecartridge housing 20 and when engaged by the switch arm contact 61 closean elec-l trical circuit to said cartridges tofire the same,

set to rotate the cam 4| at a desired speed, whereby a predeterminedlapse of time will be necessary for the cam to complete one revolutionor a portion of a revolution and move the recess 42 thereof opposite thelug 45 of the operating lever 43. The cam may, of course, be'adjusted toso locate the recess 42 that one revolution, or any portion thereof, isnecessary to move said'recess opposite the lug. During the timethat thecam 4| is rotating, the lug 54 at the lower end of the lever 43 isengaged within the recess 55 of the cam disk 56, whereby rotation of theshaft 51 and spring 84unwinds to rotate the shaft 51 throughV the mediumof the gears 58 and 59 and the pinion 8|).4 'Ihe rotation of the'shaft51 causes the switch arm 86 on said shaft to rotate, whereby the contact81 on the outer endV of said `arm passes over and engages the variouscontacts 88 on the commutator disk |59.v As the switch arm completes itsrevolution, the engagement of the contact 81 with the contacts 68completes an electrical circuit to the various cartridges 2| so as to rethe same. Inthis manner,` the. disk 58 acts as'a locking means whichprevents operation of the switch arm 68 until such time as the cam disk4| of the timing mechanism T completes its revolution. Thus, it ispossible to accurately control the exact time at which the cartridges 2|are red.

For supplying the electrical current necessary to fire the cartridges, adry cell battery 10 of any desired construction is mounted inthe upperend of the casing 26 above the plug 29 (Figure 1)`. This battery iscylindrical in cross-section and is located within an elongated sleeve1| which has its lower end secured-by screw threads to the upper portionof the plug29. An annular insulating jacket 12 is interposed between thebattery 10 and the sleeve 1| and serves to insulate said battery fromthe sleeve.` The lower end of the battery -is supported on a coiledspring 13 which is conned within the jacket 12 and the contact 10 at thelower end of said battery engages the spring. A contact screw 14 extendsthrough an axial bore formed in the plug 29 and the upper end of thisscrew carries a plate 15 which is engaged by the spring 13. With thisarrangement, the current may flow from the contact 10' oi the batterythrough the spring and to the elongate contact screw 14. The screw issuitably insulated from the plug 29 by means of an insulating sleeve 16.The lower end of the contact screw is connected by means of a wire 14awith the Contact 52 which is mounted side of the side plate 30'.

The upper end of the sleeve 1| wherein the battery 10 is mounted, isclosed by'a cap 11, which cap has an annular insulating collar 18mounted therein. A contact pin 19 is mounted axially of the insulatingcollar 18 and has itsV lower end engaging the contact 10a at the upperend of the battery 1D, whereby an electrical connection is establishedtherebetween. The upper end of the contact screw 19 is engaged by aspring pressed plunger 80 which is mounted axially in the lower portionof the plug I, which closes the upper end of the section I0. The plunger80 is metallic and, of course, contacts the metallic plug, whereby thesame is grounded and, thus, the contact 18a at the upper end of thebattery 10 is connected to ground through the screw 19 and the plunger80. The upper portion of the sleeve 1i which carries the battery 18 isaxially alined within the upper endof the casing 28 by means of aspacing collar 8| which is threadedV into said casing. A suitableilanged cap 82 surrounds the extended or projecting portion of thesleeve 1| and overlies thespacing collar 8| and the upper end of theca-sing'26. The cap is constructed of rubber, or other shock absorbingmatermi and the outer surface of thefianged cap at one contacts the boreof the section I8, whereby the casing 26 is held in axial alinement atits upper end within said section. v

From the above, it will be seen that the battery 10 is carried in theupper portion of the casing 26, while the control mechanism for flringthe cartridges 2| is carried inthe lower portion of the casing. Theupper contact 18a of the battery 18 is connected to ground through thescrew 19 and the plunger 80, while the lower contact 10 of the batteryis connected through the screw 14 and the wire 14a to the contact 52which is located on the side plate 30'. As has been explained, theoperating lever 43 controls the movement or swinging of the switch blade48 and, normally, said switch blade is riding onthe periphery of the cam4|, whereby said switch blade is out of engagement with the contact 52and in engagement with the contact 58. When engaging the contact 50, itis obvious that the switch blade 48 has opened the circuit from thebattery 10 and therefore no current is ilowing from said battery. Whenthe timing mechanism T has rotated the cam disk 4| sufficiently to movethe recess 42 opposite the lug 45 of the operating lever, said operatinglever swings to the position shown in Figure 7, whereby the switchbladeA is engaged with the contact 52. When -this occurs, the currentfrom the battery 10 mayA ow to the switch blade 48. From the switchblade the current'fiows through awire 48a downwardly to the contactprong B2 which is engaged with the contact sleeve B' in the recess B,which is located in the contact socket body 25 at the lower end of thesection I8. In this manner, the current from the battery is conducted tothe sleeve B' when the Switch blade 48 is engaging the contact 52. Thecurrent is conducted from the sleeve B' by a wire 48b which has itsupper end electrically connected to said sleeve. This wire extendsdownwardly through an opening 84 which is formed in the transversepartition |8`and has its lower end connected to the flexible switchblade 85 of a safety switch assembly E.

'Ihe safety switch assembly E includes an annular body 86 which issuitably fastened within the section |1 near the upper portion thereof.'Ihe body 88 has an axial bore 81 which has its upper end closed by aninsulating disk 88 which is suitably fastened within the upper portionthereof. The lower end of the bore of ".he body is closed by :a disk 89which is threaded thereinto.v The resilient switch blade A88 has itsupper end bolted to the insulating member 88 and the lower end of thelead wire 48h is electrically connected to this upper end. Diametricallyopposite the switch blade 85 is a second switch blade 85', similar inconstruction to the `blade 85. The upper portion of the blade 85' isalso secured to the disk 88 and a lead wire 85a has its lower endelectrically connected with said blade. The upper end of the wire 85aextends through an opening 84 `which is located axially in the partitionor plate |8 .and the extreme upper end of the wire 85a is electricallyconnected with the sleeve C' which is located in the recess C of theelectrical socket 25. In this manner, the switch blade 85 iselectrically connected with the prong C2 which engages the sleeve C' anda wire 85b leads from said prongto the switch arm 88 which travels overthe commutator disk 89.

With the abovearrangement, it will be seen that the electrical currentis conducted from the battery through the contact 52 and the switchblade 48, then through the wire 48a downwardly through the prong B2 andthe sleeve B', then through the wire 48h to the switchblade 85. When anelectrical connection is established between the switch blade 85 and theother switch 5 blade 85, as will be explained, the current flowsupwardly through the wire 85a, contact sleeve C', prong C2 and wire 85hto the switch arm 66.- Thus, the current is conducted to the contactmember G1 on said switch arm andas said arm engages the contact 68 ofthe 4commutator disk 69, the current is carriedto the latter contact 68.A wire 68a leads from each contact 68 and extends downwardly to one ofthe contact prongs D2 which is in engagement with one of the sleeves D'located in each recess D in the connecting socket 25. Each contactsleeve D has the upper end of a lead wire 68b'connected thereto and thisWire extends kdownwardly through an opening 84a in the partition I8. Thelower end of the wire 68h is connected to one of the gun cartridges 2|.Thus, when the switch arm 66 engages the contact 68 on the commutatordisk, the current flows from the contact 68 downwardly through the wire68a, contact prong D2, contact sleeve D' and wire 68h to the cartridgeconnected with said wire 68h. For housing the wires leading from thecontact sleeves D', a suitable conduit 90 is located'at one side of thesection I1 within the interior thereof (Figures 3 and 4). For packingoff around the wires 48h, 85a and 68b, which extend through thepartition I8, a suitable packing member 9| may be secured to theunderside of said partition, being held in place by a retaining ring 92.The packing member 9| has upwardly extending sleeves 9 I which extendinto the openings in the partition and surround the wires'so as toassure a seal around said wires. The provision of the packing element 9|prevents any fluid which might be in the section I1 from entering theconnecting socket 25.

From the above, it will be seen that when the timing mechanism T hasrotatedl the cam disk 4| suiliciently to swing the lever 43 so as toclose the circuit between the switch blade 48 and the contact 52,electrical current is conducted downwardly from the battery to the blade85 of the safety switch E. When said switch blade 85 has electricalconnection with the switch blade 85, the current is then conducted tothe switch arm 66 which travels over the commutator disk 69. At the sametime that the lever 43 has moved the switch blade 48 into engagementwith the contact 52, the lug 54 at the lower end of said lever has beendisengaged from the cam disk 56, which permits the switch arm 66 torotate around the commutator 69, as has been explained. 'I'herefore,when the current is conducted to the switch blade 85, the switch arm 66is rotated around the commutator disk to engage the various contacts 68for firing cartridges. Of course, if there is no electrical connectionbetween the switch .blade 85 and the switch blade 85 of the safetyswitch E, it is impossible for the cartridgeto be fired for, obviously,no current can be conducted to the switch arm 66 of the commutator.

For controlling themaking and breaking of an electrical connectionbetween the switch blades 85 and 85 an elongate operating rod 93 isdisposed axially within the lower section I1 of the housing.- The upperportion of this stem extends through an axial opening 89 in the plugwhich closes the bore of Ithe body 86 of the safety switch E, while theextreme upper end of said stem projects through an opening 88' in theinsulating disk 88 which closesthe upper end of said body. An insulatingsleeve 94 surrounds the upper portion of the rod 93 and insulates therod from the metallic body of the switch. The extreme upper end of therod 93 is movable within a guide sleeve 95 which extendsr upwardly fromthe insulating disk y8,8. A collapsible bellows 96 has its lower endsecured to the upper end of the body 86 and this bellows completelyencloses the guide sleeve 95. 'I'he upper end of the bellows is closedby a suitable plate 91 which has the wires 48h and 85a ex-y tendingtherethrough. The space around the wires extending through the plate 91is packed off by packing collars 91. f

Confined within the bore 81 of the body 86 and surrounding theinsulating sleeve 94 on the rod 93 is a metallic contact ring 98. Thisring is movable between theswitch blades and 85 and is adapted to beengaged by the offset lower ends of said switch blades. However, whenthe rod 93 is moved upwardly within the housing, the contact ring 99 isarranged to be moved upwardly beyond the offset lower ends of the switchblades 85 and 85', as shown in Figure 2, whereby said offset lower endsengage the insulating sleeve 94 and are disengaged from said contactring. -In this position, the circuit between the blades 85 and 85' isopen and there is no current flowing between said blades. When theoperating rod 93 isl moved downwardly to the position shown in Figure 4,the contact ring 98 moves between the oifset lower ends of the blades 85and 85 and since it is constructed of metal, serves to close theelectrical circuit between said blades. Therefore, when the rod 93 is inthe position shown in Figure 2, the switch formed by the blades 85 and-85 is open and it is impossible to fire the cartridges; however,downward movement of the rod moves the ring 98 between the switch bladesto close the circuit therebetween.

Theswitch blades are adapted to operate within an oil bath and to retainsaid oil within the bore 81 of the body 86, a second collapsible bellows99 has its upper end secured to the closure disk 89 `which is threadedinto the lower end ofthe body se. 'rne1ower end of the bellows issecured to a flanged collar |00 whichis confined between and externalshoulder I 0| and ,the lower end of the insulating sleeve 94. With sucharrangement the movement of the rod axially of the body 86 causes thelower bellows to be expanded or contracted in accordance with suchmovement. Thus,` the oil or other fluid which is Within' the bellows 99,body 86 and upper bellows 96 is retained in place and the switch blades85 and 85' operate at all timeswithin such fluid.

The lower end of the operating rod 93 extends through a partition |02which is mounted in a fixed position wi-thin the section I1, beingfastened therein by means of screw |03 (Figure l0). The extreme lowerend 0f the rod 93 is fastened to a plate |04 which is slidably mountedwithin the bore of the section I1. Theplate I 04 is disposed opposite orin horizontal alinement with a plurality of vertical slots |05 which areformed in the Wall of the section I1. A collar |06 surrounds the sectionI1 on the outer side of said slots and said ring is fastened to theslidable plate 04 by means of screws |01. Manlfestly, the ring I 06,plate |04 and the rod 93 fastened thereto are slidable vertically withrelation to the section I1, such movement being limited by the -lengthof the slots |05. A coiled spring |08 'which lsurrounds the section I1has its upper end engaging the underside of the collar |06, while itsllower end rests on a fixed ring |09 suitably fastened to the exterior ofthe section by screws ||0. The coiled spring |08 constantly exerts itspressure to urge the collar |06 and the plate |04 upwardly, whereby thesame are held in their uppermost positions at the upper end o! the slots|05. s A K A latch member III is located within the bore of the sectionand extends through a vertical slot I I2 provided in the stationarypartition |02. A pivot pin I |3 which extends transversely of the slot||2 also extends through the latch member |I|, whereby said member'ispivotally mounted in the partition. The upper portion of the latchmember ||I is arranged to swing outwardly through an elongate opening||4 which is formed in the wall ofthe section The lower end of thelatch'member III is tapered or reduced and is normally conned behind aretaining lug |.|5 which extends upwardly from the slidable plate-A04. Aat spring ||6, which is secured to the latch member engages' the innerwall of the section I1 and constantly urges the lower end of the latchmember inwardly, whereby the upperl end of said latch member is urgedoutwardly through the slot ||4. The engagement of the lug ||5 with thelower end of the latch member prevents such swinging of the member andholds the same normally in a position as shown in y Figure 2.

For sliding the collar |06 'andthe plate |04 downwardly in the slots |05under tension of the spring |08, whereby the operating rod 93 may bemoved downwardly from the position shown in Figure 2, a vfrictioncarriage ||1 is provided, being slidable on the exterior of the sectionI1. 'I'his carriage includes a pair of spaced collars ||8 which areconnected by friction springs IIS. The friction springs are constructedof a spring metal and are bowed outwardly, whereby they engage the boreof the well casing A. The friction spring carriage is arranged to engagethe upper end of the collar |06 to force the same downwardly and therebymove the rod S3 downwardly so that an electrical connection between theswitch blades 55 and 85' may be established, as will now be explained.

In operation, the timing mechanism T is set for a predetermined time,whereby such predetermined time is required to move the recess 42 of thecam 4| of said mechanism opposite the lug 45 of the operating lever 43.For example, if it is estimated that it will require thirty minutes tolower the device to a desired position in the well casing, then thetiming mechanism is set for thirty-live or forty minutes whereby it willrequire thirty-five or forty minutes for the recess 42 of the cam 4| tomove opposite the lug 45 of the operating lever and, therefore, thelever 43 is held in the position allowing the switch blade 48 to engagethe contact 50 until such time has elapsed. When the switch blade 48 isengaging the contact 50, the battery 10 is grounded at only oneterminal, as is clearly shown in Figure 13. At this time, the latchmember III within the section I1 is in a retracted position as shown inFigure 2,Y being held in such position by the lug |I5 on the plate |04,which plate is in its uppermost position and is retained in suchposition by the coiled spring |08. Since the plate |04 is in itsuppermost position, the rod 93 which controls the safety switch E israised. whereby the contact ring 98 offset lower ends of the safetyswitch blades and 85. Thus, there is no electrical connection betweenthe blades 85 and 85' and it is impossible to conduct any current to thecartridges 2| since such current must flowthrough said blades. With sucharrangement, the device may be lowered into the well and thereis nodanger of prematurely or accidentally firing the cartridges 2|.

As the device .is lowered into the well, the friction spring carriagerides upwardly on the lower section I1 of the housing, assuming theposition lshown in Figure 2. The parts remain in'this position duringthe lowering operation and when the desired point, at which the deviceis to be set, is reached, lowering thereof is halted. Ihe cable I5 isthen pulled upwardly whereby Vthe entire device is raised through thefriction carriage I|1 which remains stationary due to the contact of itssprings I|8 with the wall of the casing A. Upward movement of the deviceis continued until the collar |06 strikes the lower end of the frictioncarriage I|1 and when said collar engages said carriage a continuedupward movement on the device will cause the collar |06 to be moveddownwardly under tension of the spring |08 which is compressed. Itispointed out that the springs IIS of the carriage are stronger than thespring |08, whereby said carriage will remain stationary while thespring |08 is compressed to move the collar |06 downwardly. Since theplate |04 is secured to the collar |06, said plate will move downwardlytherewith, whereby the retaining lug I5 on said plate moves away fromthe lower end of the latch member As soon as said lug disengages thislower end, the latch member swings outwardly under tension of the spring|I6 to the posi-tion shown in Figure 5, whereby its upper end movesradially outwardly through the opening ||4 in the wall of the sectionI1. The downward movement of the plate |04 not only releases the latchmember III, but also moves the operating rod 93 downwardly, whereby thecontact ring 58 is moved into engagement with the switch blades 85 and85' of the safety switch E so as to make an electrical connectiontherebetween. When this occurs, the electrical lcircuit to thecommutator which controls the tiring of the cartridges is made ready,whereby when the switch blade 48 which is controlled by the timingmechanism T is engaged with the contact 52, the cartridges will be red.

After the switch blades 85 and 85' of ,the safety switch E have beenelectrically connected by the contact ring, the device is in its properposition in the well casing and the cartridges 2| are ready to be fired.At this time, the operating lever 43 has its lug riding on the peripheryof the cam disk 4I, whereby the switch blade 48 is engaging the contact50. The device is held in this position until the cam 4I has rotatedsufficiently for the lug 45 on the operating lever to move or drop intothe recess 42. At this time, the operating lever swings to swing theblade 48 into engagement with the contact 52. Such engagement of theblade 48 and the contact 52 conducts the electricalcurrent from thebattery 10 through the wire 14a, then throughthe contact 52 and theblade 48, then through the wire 48a, contact prong B2, contact sleeve B'and wire 48h to the switch blade 85. From the blade 85, the currentflows through the Contact ring 98, blade 85', wire 85a, contact isdisengaged from the sleeve C', prong C2, and nally through the wire 85hto the switch arm 66 of the commutator.

At the same time that the operating lever 43 was swung to close thecircuit between the switch blade 48 and the contact 52, the lower end ofthe lever was disengaged from the recess 55 of the retaining cam disk 56of the commutator switch arm and, therefore, as soon -as the'circuit isclosed to the switch arm, said switch arm besins its rotation around thecommutator disk 69. Such rotation of thearm causes its contact 61 tosuccessively engage the contacts 68 so as to make an electrical circuitthrough the wire 68a', contact prong D2 and contact sleeve D and thenthrough the wire 68h to Ithe respective cartridges 2|, whereby the sameare fired. Byconnecting the desired cartridges 2| with predeterminedcontacts 68 on the disk 69, it is possible to re the cartridges in anydesired order.

- When it is desired to remove tfhe device from the well, the housing islowered with relation to the friction spring carriage until the latchmember is below said carriage. As soon as the carriage ||1 movesupwardly beyond the latch member, said latch member assumesthe positionshown in Figure 12, that is, its upper end engages the underside of saidcarriage. It is then possible to lift upwardly on the cable vto removethe entire device from the well casing and the engagement of the latchmemberjwith the carriage, moves said'carriage'upwardly therewith. Theengagement of said latch member with the vcarriage prevents t'he springcarriage from moving downwardly into engagement with the collar |06,whereby the spring |08 holds the collar and the plate |04 attachedthereto in its uppermost position during the lifting of the device. Thismaintains the operating rod 93 in its raised position, whereby therev isno electrical connection between the switch blades 85 and 85 of thesafety switch. Thus, by means of the latch member and its particulararrangement, accidental or unintentional ringof any of the cartridgeswhich may remainA unred, 'is prevented during the raising of the devicethrough the well casing. p

After the device is removed from the well, the timing mechanism T, asWell as the operating spring 64, and operating lever 43 are re-set,after which the device may again be lowered to a desired position in thewell casing. It is pointed out that the device is relatively simple inconstruction and may be readily assembled or disassembled. When itisdesired to replace' the bate tery 1'0, it is only necessary to removethe plug and lift the entire casing 26 out of the upper section I0. Suchlifting is made possible because of the contact prongs which engagewithin the electrical receivingl socket 25.

In Figures 14 to 18, a slightly modified form of the invention is shown.In this form, the timing mechanism T is eliminated and a solenoid |20 issubstituted therefor. This solenoid is mounted on the inside of the sideplate 30. being bolted or otherwise fastened thereto. In thisconstruction, the upper contact a of the battery is not directlygrounded as is shown in Figure 1. Instead the spring pressed plunger 80has a wire 80a leading upwardly therefrom and this wire extends througha conical connecting member|2| which is threaded onto the 'upper end ofthe plug The upper end of the wire has electrical connection with anannular contact ring |22 which ring surrounds and is insulated from anupwardly extending shank |23 which is made integral with the connectingmember |2|. A second contact ring |24 is spaced fromthe ring |22 and isvthreaded onto `the upper endof the shank, whereby this ringisgrounded.- With t'his arrangement, the upper end' of thebattery is notconnected to ground duri-ng thelowering of the device into the well. f

Theother end 'l0' of the battery is connected by mean-s of a wire 10bwhich leads directly to the spring arm 85 of the safety switch E, theswitch blade 48 and the contacts 50 and'52 of the first form, beingeliminated. In this manner, when a ground is set up on the upper end ofthe battery, a circuit is completed directly tothe safety switch E.

For connecting the upper side of the battery 10 to ground, an elongatesleeve member |25 is arranged to be droppedrdownwandly on the 'cable |5.Thi-s sleeve member is provided with a pair oi flexible contact members|26 at its lower end, which vare adapted to engage the lower contactring |22. 'The sleeve has a second set of contact members |21 which arearranged to contact the upper contact ring |24. When the sleevel25 isdropped downwardly on the cable |5 and encloses the contact rings asshown in Figure 18, an electrical connection is established between thering |22 and the ring |24. Since the latter ring is grounded, suchelectrical connection will cause ground to be connected to the ring |22and then through the wire a to the upper side of the battery 10. Thecurrent ilows from the battery through the wire 10b to the switch blade85 of the safety switch E. W'hen the operating rod 9.8 of the device ismoved downwardly, as has been explained. to connect the switch lblade 65with the blade of the safety switch, the current will ilow from saidAblade 85' through the wireV 85a and to the switch arm 66 of thecommutator. In this form, the commutatordisk is provided with anadditional contact 68', onwhich contactrthe contact member 61 of theswitch arm 66 normally rests. Therefore, as soon as the circuit isclosed between the blades 85 and 85', a flow of current is directed tothe contact 68 because the switch arm 66 is resting on this contact.

'I'he contact 68 is connected by means of a wire |28a to the solenoid|20, whereby said sole-` noid i-s energized when the safety switch isclosed.

Energization of the solenoid v|20 -attracts an operating lever 43 whichis similar in construction to the lever`43. As the lever 43' (Figure 17)moves inwardly toward the solenoid |20, its upper end is engaged beneatha latch member |26. which latch member is constructed of a spring steelor other flexible material. After so engaged, thelever is held in thisposition against the tension of a coiled spring. 46', which is connectedto the lower end of said lever. `The extreme lower end of the lever 43'has the lug 54 thereon which is adapted to engage the recess 55 in thedisk 56 of the commutator operating mechanism.

' From the above. itwill be seen that when the sleeve |25 is droppeddownwardly on the cable, one side of the battery 10 is grounded. The0pposite side is directly connected to the safety switch E and when saidswitch is closed, the current flows through the switch arm 66 of thecommutator and thek contact 68' to energize the solenoid 20. As soon asthis occurs, the operating lever 43 is swung to disengage its lug 54from the cam disk 56. whereby said disk allows the switch arm 66 to berotated by means vof the operating spring 64, as has been explained. Thesolenoid, after being energized, is of course deenergized as soon as theswitch arm 66 moves off ofthe contact 68'. However, since the operating'.lever 43 has moved beneath the spring latch |28, said lever remains inthis position until manuallydisengaged from said latch. 'I'he remainder`of the operation of this form of the invention is exactly the same asthe rst form, hereinbefore described. Y

The foregoing description of the invention is explanatory thereofandvarious changes in the size, shape and materials, as well as in the.des tails ofv the illustrated construction may be made, within thescope of the appended claims, without departing from the spirit of theinvention. Y

What I claim and desire to secure by Letters Patent is:

1. A perforating device for a well casing including, a housing adapted'to vbe lowered into said casing onla flexible line, gun cartridgesmounted in the casing and arranged tov be electrically fired toperforate the casing, a source of electrical current supply within thehousing, a timing mechanism within thev housing' and control meanscomprising aspring actuated member associated with a timing mechanismwithin the housing for controlling. the flow of current from the sourceto the cartridges to ilre the same.

2. A perforatingdevice for a well casing including, a housingv adaptedYto be lowered into said casing on a flexible line, gun cartridgesmounted in the casing and arranged to be elec, trically red to perforatethe casing, a source of electricalcurrent supply within the housing,andrrotatable spring actuated 'control means within. the housing forkcontrolling the flow of current from the sourcel to the cartridges tofire the same. I, y

3. A perforating device for a well casing including, a housing adaptedto be lowered into said casing on a flexible line,` gun cartridgesmounted in the casing and arrangedto be electrically` red to perforatethe casing, a source of electrical current supply within the housing,control means electrically connected to thesource of supply and'to thecartridges for controlling the flow of current to the cartridges, andmeans within the housing and associated with said controly means andconnectedin the electrical circuit of the control means for preventingaccidental or unintentional operation of the same, said last named meansbeing operated to permit ilow of current to the control means uponk anupward movement `of the device within the well casing.

4. A perforating device for a well casing including, a housing adaptedto be lowered into said casing on a flexible line, gun cartridgesmounted in the casing and arranged to be electrically fired to perforatethe casing, a source of electrical current supply within the housing,control means electrically connected to the source of supply and to thecartridges for controlling the flow of current tothe cartridges, asafety switch connected in the electrical circuit between the source ofcurrent supply and the control means for preventing ow of current to thecontrol means prior to the positioning of the device in the weil casing,and means actuated by an upward movement of the Ahousing within the wellcasing for moving the safety switch to a closed position to permit aflow Aof current to the control means, whereby said safety switchrmay beclosed at any desired elevation oi the device within the well casing'. l

5. A perforating device for a well casing including, a housing adaptedto be lowered into said casing on a ilexible line, gun cartridgesmounted in the casing and arranged to be electrically red to perforatethe casing, a source of electrical current supply within the housing,means for electrically connecting the source of current supply to thecartridges, a control means interposed in the circuit between the supplyand the cartridges for controlling the flow of current to saidcartridges, an operating lever associated with the control means andnormally preventing operation thereof, and means for actuating thelever` to release the control means and permit the same to close thecircuit to the cartridges.

6. A yperforating device for a well casing including, a housing adaptedto be lowered into said casing on a exible line, gun cartridges mountedin the casing and arranged to be electricallyv tired to perforate thecasing, a source of electrical current supply within` the housing, meansfor electrically connecting the source of current supply to thecartridges, a control means interposed in the circuit between the supplyand the cartridges for controlling the ilow of current to saidcartridges, an operating lever associated with the control means andnormally preventing operation thereof, and a timing mechanism within thehousing for actuating the lever lat a predetermined time, whereby saidlever releases the control means to permit the same to operate and closethe circuit to the cartridges.

7. A perforating device for a well casing in cluding, a housing adaptedto be lowered into said casing on a' exible line, gun cartridges mountedin the casing and arranged to be electrically tired to perforate thecasing, a source of electrical current supply within the housing, aspring actuated commutatorconnected in the electrical circuit betweenthe source of current supply and the cartridges for controlling the ilowof current to said cartridges, and means associated with said commutatorfor normally preventing loperation thereof, a timing mechanism foractuating said last named means to. release said commutator when desiredto permit operation of the commutator, whereby the circuit to thecartridges is closed.

8. A perforating device for a well casing including, a housing adaptedto be lowered into said casing on a flexible line, gun cartridgesmounted in the casing and arranged to be electrically' tired toperforate the casing, a source of electrical current supply within thehousing, a spring actuated commutator connected in the electricalcircuit between the source of current supply and the cartridges forcontrolling the flow of current to said cartridges, means associatedwith said commutator for normally preventing operation thereof, a timingmechanism for actuating said last named means to release said commutatorwhen desired to permit operation of the commutator, whereby the circuitto the cartridges is closed, and a safety switch connected in theelectricalcircuit between the source of current supply and thecommutator and arrangedr to be closed when the device is properlypositioned in the well casing, whereby current cannot iiow to thecommutator and cartridges vuntil said device is in its desired position.

9. A perforating device for a well casing includinga housing adaptedv tobe lowered into said vcasing on a flexible line, gun cartridges mountedinthe casing and arranged to be electricallyiired to perforate thecasing, a source of electrical current supply within the housing, aspring actuated commutator connected in the electrical circuit betweenthe source of current supply and the cartridges for controlling the owof current to' said cartridges, means associated with said commutatorfor normally preventing operation thereof, a timing mechanism foractuating said last named means to release said commutator when desiredto permit operation of the commutator, whereby the circuit to thecartridges is closed, a safety switch connected in the electricalcircuit between the source of current supply and the commutator andarranged to be closed when the device is properly positioned in the wellcasing, whereby current cannot flow to the commutator and cartridgesuntil said device is in its desired position, and means carried by thehousing for preventing closure of the safety switch When'the device isbeing removed from the well, whereby unintentional firing of thecartridges during such removal is prevented.

10. A perforating device for a well casing including, a housing adaptedto be lowered into said casing on a ilexible line, gun cartridgesmounted in the casing and arranged to be electrically fired to perforatethe casing, a source of electrical current supply within the housing, aspring actuated commutator connectedk in the electrical circuit betweenthe source of current supply and the cartridges for controlling the flowof current to said cartridges, means associated with said commutator fornormally preventing operation thereof, means within the housing foractuating said last named means, to release said commutator when desiredto permit operation of,-the commutator, whereby the circuit to thecartridges is closed,'a safety switch connected in the electricalcircuit between the source of current supply and the commutator andarranged to be closed when the device is properly positioned in the wellcasing, whereby current cannot flow to the commutator and cartridgesuntil said device is in its desired position, a friction spring carriageslidable on the housing and associated with the safety switch forclosing said switch at the desired time, and a pivoted latch on thehousing adapted to lock the carriage against downward movement on thehousing and thereby prevent closing of the safety switch during removalof the device from the well casing.

11. A perforating device for a well casing including, a housing adaptedto be lowered into said casing on a flexible line, gun cartridgesmounted in the casing and arranged to be electrically red to perforatethe casing, a source of electrical current supply within the housing,control means electrically connected to the source of supply and to thecartridges for controlling the flow of current to the cartridges, meansfor actuating the control means at a predetermined time, a safety switchconnected in the electrical circuit between the source of current supplyand the control means for preventing fiow of current to the controlmeans prior to the vpositioning of the device in the well casing, andmeans carried by the housing and co-acting with the safety switch forpreventing closure of the safety switch when the device is being removedfrom the well, whereby unintentional firing of the cartridges duringsuch removal is prevented.

12. A perforating device for a well casing including, a housing adaptedto be lowered into said casing on a flexible line, gun cartridgesmounted in the casing and arranged to be electrically fired to perforatethe casing, a source of electrical current lsupply within the housing,means for electrically connecting the source of current supply to thecartridges, a control means interposed in the circuit between the supplyand the cartridges for controlling the ow of current to said cartridges,an operating lever associated with the control means and normallypreventing operationthereof, a timing mechanism within the housing foractuating the lever at a predetermined time, whereby said lever releasesthe control means to permit the same to operate and close the circuittothe cartridges, and a safety switch connected in the electricalcircuit between the source of current supply and the control means forpreventing flow'of current to the control means prior to the positioningof the device in the well casing.

13. A perforating device for a well casing including, ahousing adaptedto be lowered into said casing on a flexible line, gun cartridgesmounted in the casing and arranged to be electrically fired toperforate'the casing, a source of electrical current supply Within thehousing, a spring actuated commutator connected inthe electrical circuit`between the source of current supply and the cartridges for controllingthe flow of current to said cartridges, means associated with saidcommutator for normally preventing operation thereof and being arrangedyto release said commutator when desired to permit operation of thecommutator, whereby the circuit to the cartridges is closed, a safetyswitch mounted within the housing and including a pair of switch bladesconnected in the circuit between the source of supply and thecommutator,v an operating member movable within the housing and having acontact adapted to engage the blades toelectrically connect the samewhereby current is conducted to the commutator,

and means carried by the housing for holding the operating member in aposition With its contact disengaged from the switch blades during theraising and lowering of the device, through the well casing, whereby nocurrent ilows to the commutator and cartridges during such movement ofthe device through the casing and accidental firing of the cartridges isprevented.

14. A perforating device for a well casing including, a housing adaptedto be lowered into said casing on a flexible line, gun vcartridgesmounted in the casing and arranged to be electrically fired to perforatethe casing, a source of electrical current supply Within the housing,

means for electrically connecting the source of.

current supply to the cartridges, a control means interposed in thecircuit between the supply and the cartridges for controlling the flowof current to said cartridges, an operating lever associated with thecontrol means and normally preventing operation thereof, andelectrically operated means for actuating the lever, whereby said leverreleases the control means to permit the same to operate and close thelelectrical circuit to the cartridges.

15. A perforating device for a well casing including, a housing adaptedto be lowered into said casing on a exible line, gun cartridges mountedin the casing and arranged to be electrically flredto perforate thecasing, a source of electrical current supply within the housing,

means for electrically connecting the source of current supply to thecartridges, a control means interposed in the circuit between the supplyand the cartridges for controlling the now of current to saidcartridges, an operating lever associated with the control means andnormally preventing operation thereof, electrically operated means foractuating the lever, whereby said lever releases the controlmeansto'permit the same to operate and close the electrical circuit to thecartridges, Vand means adapted to rbe dropped from the surface forcompleting an electrical circuit to said electrically operated means,whereby the cartridges may be ilred at a desired time.

16. A perforating device for a well casing including, a housing adaptedto `be lowered into said casing on a ilexible line, gun cartridgesmounted in the casing and arranged to be electrically fired to perforatethe casing, a source of electrical current supply within the housing,means for electrically connecting the source of current supply to thecartridges, a control means interposed in the circuit between the supplyand the cartridges for controlling the flow or current to saidcartridges, an operating lever associated with the control means andnormally preventing operation thereof, and a solenoid for actuating thelever, whereby said lever releases the control means to permitv the sameto operate and close the electrical circuit to the cartridges.

17. A perforating device for aiwell casing including, a housing adaptedto be lowered into said casing on a flexible line, gun cartridgesmounted in the casing and arranged to be electrically red to perforatethe casing, a source of electrical current supply within the housing,means for electrically connecting the source of current supply to thecartridges, a control means interposed in the circuit between the supplyand the cartridges for controlling the flow of current to saidcartridges, an operating lever associated with the control means andnormally preventing operation thereof, a solenoid for actuating thelever, whereby said lever releases the control means to permit the sameto operate and close the electrical circuit to the cartridges, and asafety switch connected in-the electrical circuit between the source ofcurrent supply and the control means for preventing flow of current tothe control means prior to the positioning of the device in the wellcasing.

18. A perforating device for a well casing including, a housing adaptedto be lowered into said casing, gun cartridges mounted in the casing andarranged to be electrically nred to perforate the well casing, a sourceof electrical current supply within the housing and connected with thecartridges, whereby said cartridges are fired when the current isconducted thereto, a safety switch' mounted within the housing andincluding Va. pair of switch blades connected in the electrical circuitbetween the source of supply and the cartridges, and a movable operatingmember movable between and arranged to coact with the switch blades toopen and close the circuit, and means for releasably maintaining theoperating member in a position holdin the circuit open during raisingand lowering of the device through the casing, whereby no current mayflow to the cartridges during such movement of the device.

19. A perforating device for a well casing including, a housing adaptedto be lowered into said casing, gun cartridges mounted in the casing andarranged to be electrically red to perforate the well casing, a sourceof electrical current supply within the housing and connected with thecartridges, whereby said cartridges are red when the current isconducted thereto, a safety switch mounted within the housing andincluding a pair of switch blades connected in the electrical circuitbetween the source of supply and the cartridges, an operating membermovable within the housing relative to` said blades and having a contactadapted to engage the blades to electrically connect the same wherebycurrent may ilow to the cartridges, and means carried by the housing forholding the operating member in a position with its contact disengagedfrom the switch blades during raising and lowering of the device throughthe well c asing to prevent a ilow of current to the cartridges duringsuch movement.

, LEONIDAS C. MILLER..

